Single lung ventilation (SLV) is performed in patients undergoing thoracic surgery in order to cause deflation of the operative lung, thereby improving surgical conditions. Lung deflation allows for better visualization of structures in the chest, prevents intermittent expansion of the lung during ventilation (impairing access to intra-thoracic structures and interfering with surgical manipulation) and obviates the need for surgical retraction of the lung, which may cause trauma to the lung parenchyma. There are currently three methods of performing SLV in children: (1) placement of a conventional endotracheal tube (ETT) into the mainstem bronchus on the non-operative side (also called the side of the ventilated lung); (2) insertion of a balloon wedge catheter (bronchial blocker) into the mainstem bronchus on the operative side (also called the side of the operative lung); and (3) tracheal intubation with a double-lumen ETT (DLT). Each of these has several disadvantages.